Good Penetration of Moxifloxacin into Human Abscesses

Abstract

Abscesses are often treated with antibiotics in addition to incision or when incision is unfeasible, but accurate information about antibiotic abscess penetration in humans is missing. This study aimed at evaluating the penetration of moxifloxacin into human abscesses. After administration of a single dose of 400 mg moxifloxacin, drug concentrations were measured in 10 differently located abscesses at incision, and in plasma over 8 h. At incision performed 0.9–4.8 h after administration, moxifloxacin concentrations in abscesses ranged from ≤0.01 to 9.2 mg/l (1.9 ± 3.4 mg/l), indicating pronounced drug accumulation in some abscesses. The degree of abscess penetration could not be explained by covariates like the ratio of surface area to volume or pH of abscesses, or by moxifloxacin plasma concentrations. Concluding, moxifloxacin was detectable in most abscesses and may be a useful antibiotic for this indication. However, antibiotic abscess penetration was highly variable and unpredictable, suggesting surgical abscess incision whenever possible.

Transition to Oral versus Continued Intravenous Antibiotics for Patients with Pyogenic Liver Abscesses: A Retrospective Analysis

“…Abscesses are composed of an outer fibrotic wall, an inner layer of leukocytes, and a central area of necrotic debris . Penetration of antibiotics into an abdominal abscess is highly variable and unpredictable . Additionally, the acidic environment within an abscess, where pH ranges from 5.5–7.2 can also change antibiotic activity.…”

“…Previous studies indicated that abscesses likely lack active transport, and thus the equilibrium of antibiotics between serum and abscess fluid will be attained relatively slowly due to passive diffusion . However, eventually the free concentrations of antibiotics within the abscess will be equal or higher to that in serum concentration because antibiotics inside the abscess are not being metabolized or excreted . This form of antibiotic trapping is believed to favor time‐dependent antibiotics, such as β‐lactams, whose bactericidal effectiveness is optimized when the time of bacterial exposure to the antibiotic is maximized .…”

“…12 Penetration of antibiotics into an abdominal abscess is highly variable and unpredictable. [13][14][15] Additionally, the acidic environment within an abscess, where pH ranges from 5.5-7.2, 12 can also change antibiotic activity. In an acidic environment, antibiotics can undergo electrochemical changes that decrease the passage across bacteria membranes.…”

“…17 However, eventually the free concentrations of antibiotics within the abscess will be equal or higher to that in serum concentration because antibiotics inside the abscess are not being metabolized or excreted. 12,13,[17][18][19] This form of antibiotic trapping is believed to favor time-dependent antibiotics, such as b-lactams, whose bactericidal effectiveness is optimized when the time of bacterial exposure to the antibiotic is maximized. 20 Conversely, fluoroquinolones, which are generally known to have good penetration into tissues, are concentration-dependent drugs, meaning they exert a higher rate of bacterial killing with higher antibiotic concentrations.…”